• Journal of agriculture & life science
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• v.50 no.5
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• pp.1-9
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• 2016

Plant growth and development strongly influenced by light quantity and its spectral composition. Young tomato plants were cultivated in growth cabinets under artificial light provided by red and blue light emitting diodes(LEDs) during 12 hours, then plants were exposed to monochromatic ultraviolet, blue, green and red lights as an end-of-day(EOD) treatment during 4 hours to study their effect on plant growth parameters. EOD lighting from various LEDs increased total fresh and dry weights as well as assimilation area compared to those in control. Blue light increased stem height, internode length and stem diameter. Monochromatic UV-A light reduced stem elongation, highly increased stomatal conductance. Compactness and health index of young tomato plants were increased in UV-A and red light treatments.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.170-177
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• 2017

This study was conducted to estimate the light pollution damage caused by night-break lighting in 'Kyoho' grapes. Night irradiation was performed every night for four hours (10 p.m. to 2 a.m.) from the full bloom to the harvest stage using red, blue, and white lamps as artificial light. Fruit yield, soluble solid content, anthocyanin content, and chlorophyll a content were affected by night irradiation. The soluble solid content of the control was $17.5^{\circ}Brix$, approximately $1^{\circ}Brix$ higher than the red ($16.4^{\circ}Brix$), blue ($16.2^{\circ}Brix$), and white light treated grapes ($16.3^{\circ}Brix$). The anthocyanin content of the skin was also higher in the control at $4.08{\mu}g{\cdot}cm^{-2}$ compared to the red ($3.14{\mu}g{\cdot}cm^{-2}$), blue ($2.47{\mu}g{\cdot}cm^{-2}$), and white ($2.82{\mu}g{\cdot}cm^{-2}$) light treated samples. On the other hand, the chlorophyll a content of the control was the lowest at $0.268{\mu}g{\cdot}cm^{-2}$ as compared with the red ($0.339{\mu}g{\cdot}cm^{-2}$), blue ($0.345{\mu}g{\cdot}cm^{-2}$), and white ($0.372{\mu}g{\cdot}cm^{-2}$) light treated samples. Considering that higher soluble solid contents, higher accumulation of anthocyanin, and lower chlorophyll a contents are factors involved in fruit maturation, night irradiation may delay fruit maturation and red light treatment may result in decreased yield. Our results confirmed that night-break lighting regardless of the wavelength provoked light pollution in 'Kyoho' grapes. Therefore, fruit maturation may be poor in the presence of artificial light, including streetlamps, in neighboring vineyards.

• Journal of Bio-Environment Control
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• v.8 no.4
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• pp.275-280
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• 1999

This study was conducted to investigate the effects of $CO_2$ concentration(310 or 950$\mu$ mol.mol$^{-1}$ ) and air current speed(0.3, 0.5, 0.7 or 0.9m.s$^{-1}$ ) on the growth and development of eggp1ant Plug seedlings (Solanum melongena L.) under artificial 1ighting. For the treatment of $CO_2$ enrichment, stem length and diameter, the ratio of stem length to stem diameter, plant height, leaf area, net photosynthetic rate, top dried weight were significantly different at 1% level. Stem length of plug seedlings decreased at the condition under enriched $CO_2$ and high air current speed above plug stand. Stem diameter of plug seedlings increased and plant height decreased with the increasing $CO_2$ concentration. Plug seedlings had maximum net photosynthetic rate at the air current speed of 0.7m.s$^{-1}$ . Net photosynthetic rate at $CO_2$ concentration of 950$\mu$mol.mol$^{-1}$ increased by 46% than those at 310$\mu$mol.mol$^{-1}$ . Thus $CO_2$ enrichment would be effective for the production of plug seedlings with high quality.

• Journal of Bio-Environment Control
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• v.30 no.3
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• pp.237-243
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• 2021

The objective of this study was to evaluate the effect of stem number on plant growth, fruit quality, and yield of sweet peppers grown in greenhouses under supplemental lighting in winter. The seedlings were transplanted at 3.2 plants·m^-2 on October 26, 2020, and started supplemental lighting with 32 high pressure sodium lamps for 16-hour photoperiod from December 1, 2020 to May 25, 2021. Stems were differently trained with 2 and 3 numbers after branching nodes were developed. In the final harvest, the plant height was significantly shorter in the 3 stem-plants than in the 2 stem-plants. The number of nodes per stem and the leaves per plant were increased in the 3 stem-plants than in the 2 stem-plants, while the leaf area was less affected. There were no significant differences in the dry mass of leaves, stems, and immature fruits between the 2 and 3 stem-plants. The fruit fresh weight and fruit dry weight in the 3 stem-plants were decreased by 17% and 12% at 156 days after transplanting (DAT), and by 17% and 15% at 198 DAT compared to those in the 2 stem-plants, respectively. The marketable fruit rates were 93.6% and 95.4% in the 2 and 3 stem-plants, respectively. The total fruit yield in the 3 stem-plants was increased by 30.2% as compared to that in the 2 stem-plants. We concluded that the 3-stem-training cultivation positively affected the total fruit yield by sustaining adaptive vegetative growth of the plants. This result will help producers make useful decisions for increasing productivity of sweet peppers in greenhouses.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.488-494
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• 2001

Seedlings of strawberry, 'Reiko' were planted in plastic pots of 24 cm in diameter in the middle of September in 1995, 1996, and 1997. Ten plants were transferred to greenhouse with artificial illumination at 5-day interval from late September to late January. The deepest dormancy of 'Reiko' in Daegu area was found to be on November 5, October 25, and October 31 in 1995, 1996, and 1997, respectively. The time for moving plants to make the plants grow in semi-dormant state in the greenhouse occurred between Nov. 10 and Nov. 20 in both 1995 and 1996, and between Nov. 10 and Nov. 30 in 1997. The time passing approximately 100-200 cumulative hours of exposure to below $5^{\circ}C$ canopy temperature from the peak dormancy, which is required for breaking dormancy of 'Reiko', was between November 16 and 25 in 1996, and November 24 and December 5 in 1997. 'Reiko' yielded high every year when seedlings were moved into greenhouse during the period of October to November. The plants gave good response to forcing culture under lighting. The right time for moving plants into greenhouse in semi-forcing culture appeared to be the time passing 50-150 cumulative hours of exposure to below $5^{\circ}C$ canopy temperature from the peak dormancy.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.9-17
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• 2009

Discomfort Glare from the artificial light sources is an important issue in assessment of lighting quality for healthy buildings. Glare, as a factor of the characteristics of brightness, which has been defined as the sensation produced by contrast and luminance within an entire field view, unfavorably influences the occupants who performs visual tasks. It may cause annoyance and discomfort by interruption of visibility. In the whole visual field, glare can be determined by effects of the position, the luminance and the size of the light source and brightness of the surroundings. Therefore, experimental equipment is required to maintain a constant visual lighting environment. Recent studies have been developed and used the instrument for glare sensation evaluation but the instruments showed some difficulties to verify the correlation of glare indicators. The instrument have been developed with reference to former studies. It is called the Glare Tester. This is consist of 2[m]-diameter vertical dome screen painted with white flat paint, and light sources installed inside the screen. These light sources can provide various range of brightness at any inner surface of the screen. 2 Glare light sources can provide the value of luminance within the range of $0{\sim}150,000[cd/m^2]$. Moreover, 12 light sources are used for background luminance and it can perform the value of luminance within the range of $0{\sim}350[cd/m^2]$. Several experiments have been conducted using this Glare Tester to evaluate the range of the visibility, the values of BCD and the glare sensation in lower and upper visual field.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1597-1609
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• 2004

A lot of lipreading system has been proposed to compensate the rate of speech recognition dropped in a noisy environment. Previous lipreading systems work on some specific conditions such as artificial lighting and predefined background color. In this paper, we propose a real-time lipreading system which allows the motion of a speaker and relaxes the restriction on the condition for color and lighting. The proposed system extracts face and lip region from input video sequence captured with a common PC camera and essential visual information in real-time. It recognizes utterance words by using the visual information in real-time. It uses the hue histogram model to extract face and lip region. It uses mean shift algorithm to track the face of a moving speaker. It uses PCA(Principal Component Analysis) to extract the visual information for learning and testing. Also, it uses HMM(Hidden Markov Model) as a recognition algorithm. The experimental results show that our system could get the recognition rate of 90% in case of speaker dependent lipreading and increase the rate of speech recognition up to 40～85% according to the noise level when it is combined with audio speech recognition.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.439-445
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• 2017

Transplant production in a plant factory with artificial lighting provides several benefits; (1) rapid and uniform transplant production, (2) high production rate per unit area, and (3) production of disease free transplants production. To improve the growth of runner plants when strawberry transplants are produced in a plant factory, we conducted two experiments to investigate (1) the effect of different light intensity for stock and runner plants on the growth of runner plants, and (2) the effect of different container volume for runner plants on their growth. When the stock and runner plants were grown under nine different light conditions composed of three different light intensities (100, 200, and $400{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPF) for each stock and runner plants, increasing the light intensity for stock plants promoted the growth of runner plants, however, the growth of runner plants was not enhanced by increasing the light intensity for runner plants under same light intensity condition for stock plants. We also cultivated runner plants using plug trays with four different container volumes (21, 34, 73, and 150 mL) for 20 days after placing the stock plants, and found that using plug trays with lager container volume did not enhance the growth of runner plants. These results indicate that providing optimal condition for stock plants, rather than the runner plants, is more important for increasing the growth of the runner plants and that the efficiency of strawberry transplant production in a plant factory can be improved by decreasing light intensity or container volume for runner plants.

• Journal of Biosystems Engineering
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• v.22 no.3
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• pp.311-316
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• 1997

Two methods were used to detrermine the net photosynthetic rate(NPR) in the plug stand using a wind tunnel for plug seedlings Production. One is called as the integration method in which NPR calculated by the use of air current speed and $CO^2$ concentration measured at any heights above the medium surface in a wind tunnel were summed. It was assumed that the air flow at any layer did not mix with the lower or upper air layer. The other is called as the diffusion method in which eddy diffusivities above the plug stand were used to determine the NPR in the plug stand. In this method, $CO^2$ above or inside the plug stand was assumed to be absorbed vertically. NPR determined by the diffusion method was 28~45% of the NPR calculated by the integration method. Considering the magnitude of NPR and the effects of the air current speed on NPR, the integration method would be adequate for the calculation of NPR in the plug stand. Maximum NPR determined using the integration method appeared at the air current speed of 0.7m $s^{-1}$. It was ascribed to the decreased diffusion resistances of $CO^2$ with the increasing air current speed. NPR at the rear region in plug stand was 20~34% lower than that at the front region. NPR sharply decreased with the increase of an elapsed time after the beginning of photoperiod. Therefore $CO^2$ enrichment would be effective to force the growth of plug seedlings in a semi-closed ecological system under artificial lighting.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.700-710
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• 2011

This study is to explore the characteristics and trends of the interior design of the residence area of the cruise ships. The interior of the cruise ships running three Asian countries - Korea, Japan and China was analyzed to understand the design of the public area and the cabin area. The interior of the ships showed the modern, high-tech style with their unique concept. Also, the feeling of the openness was emphasized in two ways- the visual and psychological expression and the spatial application. The contrast of color and the effect of artificial lighting used to express the extended feeling of the closed space inside the cruise ship. The results are expected to contribute to understand the interior design of the worldwide cruise ship and be used as a valuable data for the development of the interior design of the cruise ship.